The Z Machine at Sandia National Laboratories produces 25MA, 100-ns current pulses to generate high energy density conditions. Physical processes in the Magnetically Insulated Transmission Line (MITL) region near the target create plasmas on the anode and cathode electrodes, seed parasitic current loss, and reduce experiment performance. Lightly-bound surface contaminants are known to be the primary constituents of electrode plasmas which contribute to loss mechanisms. We have developed an in-situ plasma discharge process that utilizes the MITL electrodes to excite a cleaning plasma. An Argon-Oxygen plasma sputters and chemically reacts low-Z contaminants from electrode surfaces prior to the shot. This process was employed on Sandia’s Mykonos accelerator with a diagnostically accessible load so that changes in plasma formation could be directly observed. The conductors carry lineal current densities sufficient to desorb contaminants and produce Z-like MITL conditions. Data suggests that electrode plasma formation is delayed and contaminant inventory reduced when cleaning is used. Gated imagers have observed 3-5 times lower electrode plasma self-emission intensity during the 130-ns, 650-kA pulse. These may be the first direct observations of such behavior.